On the 6th of June, 1881, an instantaneous view was taken, by your direction, of the execution of a condemned mule belonging to the Engineer Department. A small bag containing 6 ounces of dynamite and a fuse was fastened on the mule's forehead, the wires from the fuse connecting with a magneto-electric machine. The camera was placed at a distance of about 47 feet from the mule and properly focussed; the drop shutter was held up by a string, fastened to another fuse, which was placed in the same circuit with the first, so that both were fired simultaneously and the shutter allowed to drop. The result was a negative showing the mule in an upright position, but with his head blown off. This photograph has excited much interest and comment in the scientific world. A very narrow slit was used in the shutter, and as nearly as can be estimated the time of exposure was about 1/750 of a second. A 10 by 12 gelatino-bromide instantaneous Eastman dry plate was used, with a 4 D Dallmeyer lens, using the full opening.